1. Field of the Invention
In strata control tasks for both mining and civilian applications, it is necessary to have reinforcement systems that provide increasing reliability and better installation times, thus increasing safety and reducing the time involved in carrying out said tasks.
This invention refers to a reinforcement bolt with immediate mechanical anchoring and subsequent injection option.
2. Description of Related Art
There are various reinforcement techniques and elements currently employed in strata control. Of particular interest to this application are bolts and rods. Reinforcement systems may be classified in various ways. Among them according to the work load are passive anchors, active anchors and mixed anchors. According to their supporting mechanism adhesive anchors and friction anchors can be found. For adhesive anchors, the annular space between the bolt and the perforation is filled with resin or cement mortar, which upon curing, offers sufficient adhesiveness to cement the rod to the terrain. Friction anchors employ expansion heads and elements that expand and interact with rock at the moment that tension is applied to the anchor.
According to their shape, manufacture or operating principle: helical bolts, self-drilling bolts, smooth rods threaded at either end, grooved rods, and grooved rods threaded at either end, etc. are also found.
Helical bolts are resistant transversal section rods, oval-shaped, with projections shaped like a large-bore, left-handed thread. They are manufactured by means of hot rolling. A nut or threaded element can be placed on its thread, and it may roll lengthwise along the projections, thus generating the desired anchoring.